How can I remove unwanted part of an image with OpenCV using C++?

Question

This is my input image:

and I would like to remove letterings from my image (Ex. DINING ROOM). How could I do this?

My code is below.

Mat skel;
Mat image=imread("InputImage4.jpg",1);
cvtColor(image,image,CV_BGR2GRAY);
threshold(image,image,50,255,THRESH_BINARY_INV);
WallFinder wall;
wall.setLineLengthAndGap(100,20);
wall.setMinVote(80);
skel=wall.skeleton(image);

Mat skeleton(Mat& img)
    {
        threshold(img, img, 50, 255, THRESH_BINARY); 
        Mat skel(img.size(), CV_8UC1, Scalar(0));
        Mat temp;
        Mat eroded;
        Mat element = getStructuringElement(MORPH_CROSS, Size(3, 3));
        bool done;      
        do
        {
          erode(img, eroded, element);
          dilate(eroded, temp, element);
          subtract(img, temp, temp);
          bitwise_or(skel, temp, skel);
          eroded.copyTo(img);
          done = (countNonZero(img) == 0);
        } while (!done);
        dilate(skel,skel,Mat(),Point(-1,-1),2);
        erode(skel,skel,Mat(),Point(-1,-1),2);
        return skel;
    }

And this my output image:

enter image description here

I must first remove letterings to do my job. (Like BATH)

So you need to do it manually ?

Haris
– Haris

2013-11-19 11:04:11 +00:00
Commented Nov 19, 2013 at 11:04 — Haris
– Haris, Commented Nov 19, 2013 at 11:04

scap3y · Accepted Answer · 2013-11-19 12:09:38Z

1

Use the text-detection project described here to detect the area where text is present and then simply apply the color which has the maximum occurence in your image (i.e., the background) and voila.!

HTH

answered Nov 19, 2013 at 12:09

scap3y

1,19810 silver badges27 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Haris · Accepted Answer · 2013-11-19 11:27:20Z

Here is a the code I made for cropping images, and made little modification to meet your requirement. And you need to manually select the area to remove.

#include <iostream>
#include "opencv2/opencv.hpp"
#include <stdio.h>

using namespace std;
using namespace cv;


Mat src,img,ROI;
Rect cropRect(0,0,0,0);
 Point P1(0,0);
 Point P2(0,0);

const char* winName="Crop Image";
bool clicked=false;
int i=0;
char imgName[15];


void checkBoundary(){
       //check croping rectangle exceed image boundary
       if(cropRect.width>img.cols-cropRect.x)
         cropRect.width=img.cols-cropRect.x;

       if(cropRect.height>img.rows-cropRect.y)
         cropRect.height=img.rows-cropRect.y;

        if(cropRect.x<0)
         cropRect.x=0;

       if(cropRect.y<0)
         cropRect.height=0;
}

void showImage(){
    img=src.clone();
    checkBoundary();
    rectangle(img, cropRect, Scalar(0,255,0), 1, 8, 0 );
    imshow(winName,img);
}


void onMouse( int event, int x, int y, int f, void* ){


    switch(event){

        case  CV_EVENT_LBUTTONDOWN  :
                                        clicked=true;

                                        P1.x=x;
                                        P1.y=y;
                                        P2.x=x;
                                        P2.y=y;
                                        break;

        case  CV_EVENT_LBUTTONUP    :
                                        P2.x=x;
                                        P2.y=y;
                                        clicked=false;
                                        break;

        case  CV_EVENT_MOUSEMOVE    :
                                        if(clicked){
                                        P2.x=x;
                                        P2.y=y;
                                        }
                                        break;

        default                     :   break;


    }


    if(clicked){
     if(P1.x>P2.x){ cropRect.x=P2.x;
                       cropRect.width=P1.x-P2.x; }
        else {         cropRect.x=P1.x;
                       cropRect.width=P2.x-P1.x; }

        if(P1.y>P2.y){ cropRect.y=P2.y;
                       cropRect.height=P1.y-P2.y; }
        else {         cropRect.y=P1.y;
                       cropRect.height=P2.y-P1.y; }

    }


showImage();


}
int main()
{

    cout<<"Click and drag for Selection"<<endl<<endl;
    cout<<"------> Press 's' to save"<<endl<<endl;
    cout<<"------> Press 'e' to reset"<<endl;
    cout<<"------> Press 'r' to reset"<<endl<<endl;
    cout<<"------> Press 'Esc' to quit"<<endl<<endl;


    src=imread("img.jpg",1);

    namedWindow(winName,WINDOW_NORMAL);
    setMouseCallback(winName,onMouse,NULL );
    imshow(winName,src);

    while(1){
    char c=waitKey();
    if(c=='s'&&ROI.data){
     sprintf(imgName,"%d.jpg",i++);
     imwrite(imgName,img);
     cout<<"  Saved "<<imgName<<endl;
    }

    if(c=='e') {
        if(cropRect.width>0&&cropRect.height>0){
        ROI=src(cropRect);
        ROI.setTo(Scalar(255,255,255));
        showImage();
       }
    }

    if(c==27) break;
    if(c=='r') {cropRect.x=0;cropRect.y=0;cropRect.width=0;cropRect.height=0;}
    showImage();

    }


    return 0;
}

Result:- enter image description here

Thanx so much. However I will not use mouse events. The deletion processing will be automatic.
So you should use some thing like contour finding, check for small contour, find bounding rect for each small contour, erase the region with bounding rect etc...

Collectives™ on Stack Overflow

How can I remove unwanted part of an image with OpenCV using C++?

2 Answers 2

Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related